Author Topic: How we draw a usecase diagram from a case study?  (Read 2261 times)

Vasantharaj

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How we draw a usecase diagram from a case study?
« on: September 22, 2016, 04:17:51 pm »
The following steps are followed
1. Information which we do not model in use case diagrams are
    (i) Name of the systems
    (ii) Architectures
   (iii) Database names
   (iv) Networks
   (v) Brand names
   (vi) Technology names
2. Differentiate information against actions.
3. Write all sequence of actions.
4. Try to find out which actor is performing the above section.
5. Try to identify essential use cases and supporting use cases.
6. Try to identify some modules with respect to functionality.
7. Try to draw the diagram appropriately between use cases and actors

Swathi894

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Re: How we draw a usecase diagram from a case study?
« Reply #1 on: November 18, 2016, 02:56:46 am »
Use Case Diagram is a high-level diagram of all other UML diagrams.
- The main focus of the UCD will be on how the external interfaces (end users, support systems, special databases and third party) interacts with the proposed IT System.
- This interaction initiates a Business function/functionality called as a 'Use Case' shown with an ellipse symbol.
- Use cases are used to describe the functionality of a system in a horizontal way, rather than representing the details of individual features
   in the system, UCDs can show all necessary functionalities.
- UCDs are not sequence diagrams or flow charts because they do not show the order(sequence) of action or the number of times the 
   system actions and sub-actions are to be executed and also doesn't mention the time frame.
4 Major Elements of UCDs:[/b]
1.   Actors (can be a living or non-living things) (Actors are NOUNS)
2.   The system itself (rectangular box)
3.   The Use Cases (Essential UC – Makes sense and completeness to end users, and Supporting UCs – Makes sense and support
        Essential UCs) (UCs are VERBS)
4.   The lines that represent the relationship between the elements. (Generalize -> Generalization refers to “A kind of”
        Here there are parent class and child class. A parent class cannot exist without child class.
        Include -> Compulsory-> Parent class cannot exist without child class.
        Extend -> Optional -> Child class exists without Parent class.
5.   System clock (Automation):  The system clock refers to the automatic responses from the system to the end users to perform
         function in the desired way.

Guidelines to draw a UCD from a case study:
1.   Information that is not covered in the UCD is as follows,
•   Names of the systems (laptop, desktops, Workstations).
•   Architectures (2 tier, 3 tier, ‘n’ tier, client server.
•   Names of DB (DB2, SQL Server, My SQL).
•   Networks (LAN, WAN, Internet).
•   Names of the brands (HP, Lenovo, Wipro, Sony).
•   Names of the technologies (Java, Net, Mainframes)
2.   Differentiate Actions from Information.
3.   Write the sequence of actions.
4.   Try to match action with an actor.
5.   Identify Essential use cases and Supporting use cases.
6.   Identify modules in relation to usage or functionality.
7.   Draw appropriate relationships (generalize, include, extend) between Actors and Use cases.

rakesh chary

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Re: How we draw a usecase diagram from a case study?
« Reply #2 on: November 30, 2016, 11:50:08 am »
The following steps are followed
1. Information which we do not model inuse case diagrams are
    (i) Name of the systems
    (ii) Architectures
   (iii) Database names
   (iv) Networks
   (v) Brand names
   (vi) Technology names
2. Differentiate information against actions.
3. Write all sequence of actions.
4. Try to find out which actor is performing the above section.
5. Try to identify essential use cases and supporting use cases.
6. Try to identify some modules with respect to functionality.
7. Try to draw the diagram appropriately between use cases and actors

vardhini

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Re: How we draw a usecase diagram from a case study?
« Reply #3 on: December 10, 2016, 07:32:30 pm »
Use case can be indirectly called as mother of all diagrams.
First and most important thing is that go thoroughly the case study and identify the following parameters.
a)Actors
b)system(what they want to develop)
c)Use cases
d)lines(Represents the relationship between them)
Step -1
Differentiate the Actors information and their  assigned work in that particular case study.
NOTE:Actors they may be living or non living things
They should represent by noun
Actors always stay away from system boundary.
Step-2
Write  actions according to sequence.
step-3
Make sure which actor is performing there particular actions.
Step-4
Identify the Essential use cases and supporting use cases.
NOTE:
Essential use cases make sense and gives completeness to end user
Supporting use case supports the essential use case.
step-5
Draw the relationship appropriately between the identify   actors and use cases.

171525904

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Re: How we draw a usecase diagram from a case study?
« Reply #4 on: July 04, 2017, 02:35:32 pm »
Steps To draw Use case Diagram.

1)Define Primary actors
2)Define if any actor generalization exist
3)Define secondary actor
4)Define essential use cases (Action)
5)Define specialize use cases
6)Define associations
7)Define include relationship
8)Define exclude relationship
9)Define Automation   

170123204

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Re: How we draw a usecase diagram from a case study?
« Reply #5 on: July 07, 2017, 11:48:56 am »
The following steps are followed
1. Information which we do not model in use case diagrams are
    (i) Name of the systems
    (ii) Architectures
   (iii) Database names
   (iv) Networks
   (v) Brand names
   (vi) Technology names
2. Differentiate information against actions.
3. Write all sequence of actions.
4. Try to find out which actor is performing the above section.
5. Try to identify essential use cases and supporting use cases.
6. Try to identify some modules with respect to functionality.
7. Try to draw the diagram appropriately between use cases and actors


172031605

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Re: How we draw a usecase diagram from a case study?
« Reply #6 on: August 02, 2017, 04:37:26 pm »
Use case diagrams are considered for high level requirement analysis of a system. When the requirements of a system are analyzed, the functionalities are captured in use cases.

We can say that use cases are nothing but the system functionalities written in an organized manner. The second thing which is relevant to use cases are the actors. Actors can be defined as something that interacts with the system.

Actors can be a human user, some internal applications, or may be some external applications. When we are planning to draw a use case diagram, we should have the following items identified.

    Functionalities to be represented as use case

    Actors

    Relationships among the use cases and actors.

Use case diagrams are drawn to capture the functional requirements of a system. After identifying the above items, we have to use the following guidelines to draw an efficient use case diagram

    The name of a use case is very important. The name should be chosen in such a way so that it can identify the functionalities performed.

    Give a suitable name for actors.

    Show relationships and dependencies clearly in the diagram.

    Do not try to include all types of relationships, as the main purpose of the diagram is to identify the requirements.

    Use notes whenever required to clarify some important points.

Following is a sample use case diagram representing the order management system. Hence, if we look into the diagram then we will find three use cases (Order, SpecialOrder, and NormalOrder) and one actor which is the customer.

171035406

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Re: How we draw a usecase diagram from a case study?
« Reply #7 on: August 27, 2017, 04:36:24 pm »
Steps to draw Use case diagrams:

      Information which we do not model in use case diagrams are:
         Name of the systems,architectures,databases names,networks,brand names.

      Differentiate information against actions.

      Write all sequence of actions.

      Find out which actor is performing the above action.

      Indentify essential use case and supporting use cases.

      Identify some modules with respect to functionality or usage.

      Draw the relationship appropriately between the identified actors and use cases.

Pranjal Dutta

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How we draw a usecase diagram from a case study?
« Reply #8 on: August 29, 2017, 03:58:27 pm »
Use case Diagram is the most important and essential tool for Business Analyst. In layman, Use case Diagram is a medium for the business owner to understand how the proposed system will work and for the developer to understand what they need to prepare.
So to draw the Use case Diagram from a case study, we need to follow the below steps:
1. Need to identify the actor(s) from the information given in the case study. (Actors are those who interact with system).
2. Need to write all sequence of Actions.
3. Need to identify which actor is performing what action(s).
4. Need to identify the essential and supporting Use Cases (use case are the services that system knows how to perform).
5. Need to draw appropriate relationship between the identified Actor(s) and Use-Case(s).
6. And yes, some information we need to keep in mind that cannot be used in the Use case Diagram:
    a. Name of the system, Type of Database, Type of Network, Name of the technologies, Brand name.

1170220109

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Re: How we draw a usecase diagram from a case study?
« Reply #9 on: October 18, 2017, 05:34:35 pm »
1)The information which we do not model in use case diagrams are
Name of the systems, architectures, database names, networks, brand names, technology names.
2)Differentiate among different actors
3)Write all sequences of actions
4)Try to find out which actor is performing above action
5)Try to identify Essential use cases and Supporting use cases
6)Try to identify some modules with respect to the functionality
7)Try to draw the relationships appropriately in between the identified actors and Use cases.

1171429410

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Re: How we draw a usecase diagram from a case study?
« Reply #10 on: January 01, 2018, 03:03:17 pm »
The steps involved in drawing a usecase diagram from a case study are:
1. Analyze the different actions to be performed as per the case study.
2. Put all the actions in a sequential order.
3. Analyze the actor who is performing the actions in case study.
4. Figure out essential use case and supporting use case.
5. Identify some modules with respect to functionality or usage.
6. Formulate the relationship between Actors and Usecases.

Note: Information need not to be included in usecase are:
1. Database names
2. Brand names
3. Technology names
4. Architectures

1172540111

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Re: How we draw a usecase diagram from a case study?
« Reply #11 on: January 02, 2018, 10:52:28 pm »
First, list out all the actions that you think are necessary, then see if the actions really meet the objective, and take out unnecessary actions. Do the same with Actors. After finalizing the Actions and Actors, start mapping, use Generalization, Include and Extend relations where ever necessary according to the case study(Include for mandatory fields, Extend for optional fields and generalization for either-or cases). If any actor generalization is necessary then connect them.

1173025009

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Re: How we draw a usecase diagram from a case study?
« Reply #12 on: January 03, 2018, 08:28:10 pm »
What is a Use Case Diagram?
•   A use case diagram is a dynamic or behaviour diagram in UML.
•   Use case diagrams consists of actors, use cases and their relationships.
•   The diagram is used to model the system/subsystem of an application.
•   A single use case diagram captures a particular functionality of a system.
Why Make Use Case Diagrams?
The purpose of use case diagram is to capture the dynamic aspect of a system. However, this definition is too generic to describe the purpose, as other four diagrams (activity, sequence, collaboration, and Statechart) also have the same purpose. They also help identify any internal or external factors that may influence the system and should be taken into consideration.
They provide a good high level analysis from outside the system. Use case diagrams specify how the system interacts with actors without worrying about the details of how that functionality is implemented.

Basic Use Case Diagram Symbols and Notations

System
Draw your system's boundaries using a rectangle that contains use cases. Place actors outside the system's boundaries.
 

Use Case
Draw use cases using ovals. Label the ovals with verbs that represent the system's functions.
 

Actors
Actors are the users of a system. When one system is the actor of another system, label the actor system with the actor stereotype.
 

Relationships
There can be 5 relationship types in a use case diagram.
•   Association between actor and use case
•   Generalization of an actor
•   Extend between two use cases
•   Include between two use cases
•   Generalization of a use case
Association Between Actor and Use Case
This one is straightforward and present in every use case diagram. Few things to note.
•   An actor must be associated with at least one use case.
•   An actor can be associated with multiple use cases.
•   Multiple actors can be associated with a single use case.
 
Different ways association relationship appears in use case diagrams
Generalization of an Actor
Generalization of an actor means that one actor can inherit the role of the other actor. The descendant inherits all the use cases of the ancestor. The descendant has one or more use cases that are specific to that role. Let’s expand the previous use case diagram to show the generalization of an actor.
 
A generalized actor in an use case diagram
Extend Relationship Between Two Use Cases
Many people confuse the extend relationship in use cases. As the name implies it extends the base use case and adds more functionality to the system. Here are few things to consider when using the <<extend>> relationship.
•   The extending use case is dependent on the extended (base) use case. In the below diagram the “Calculate Bonus” use case doesn’t make much sense without the “Deposit Funds” use case.
•   The extending use case is usually optional and can be triggered conditionally. In the diagram, you can see that the extending use case is triggered only for deposits over 10,000 or when the age is over 55.
•   The extended (base) use case must be meaningful on its own. This means it should be independent and must not rely on the behavior of the extending use case.
Lets expand our current example to show the <<extend>> relationship.
 
Extend relationship in use case diagrams
Include Relationship Between Two Use Cases
Include relationship show that the behavior of the included use case is part of the including (base) use case. The main reason for this is to reuse the common actions across multiple use cases. In some situations, this is done to simplify complex behaviors. Few things to consider when using the <<include>> relationship.
•   The base use case is incomplete without the included use case.
•   The included use case is mandatory and not optional.
Lest expand our banking system use case diagram to show include relationships as well.
 
Includes is usually used to model common behavior
Generalization of a Use Case
This is similar to the generalization of an actor. The behavior of the ancestor is inherited by the descendant. This is used when there is common behavior between two use cases and also specialized behavior specific to each use case.
For example, in the previous banking example, there might be a use case called “Pay Bills”. This can be generalized to “Pay by Credit Card”, “Pay by Bank Balance” etc.

How to Draw a Use Case Diagram?
Use case diagrams are considered for high level requirement analysis of a system. When the requirements of a system are analyzed, the functionalities are captured in use cases.
We can say that use cases are nothing but the system functionalities written in an organized manner. The second thing which is relevant to use cases are the actors. Actors can be defined as something that interacts with the system.
Actors can be a human user, some internal applications, or may be some external applications. When we are planning to draw a use case diagram, we should have the following items identified.
•   Functionalities to be represented as use case
•   Actors
•   Relationships among the use cases and actors.

Use case diagrams are drawn to capture the functional requirements of a system. After identifying the above items, we have to use the following guidelines to draw an efficient use case diagram
•   The name of a use case is very important. The name should be chosen in such a way so that it can identify the functionalities performed.
•   Give a suitable name for actors.
•   Show relationships and dependencies clearly in the diagram.

1173025809

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Re: How we draw a usecase diagram from a case study?
« Reply #13 on: January 12, 2018, 12:10:22 am »
The various steps involved in creating a use case diagram from a case study can be stated as -
1. Read the case carefully to find out all the actions to be performed.
2. Identifying Actors, who are the external entities that interact with the system.
3. Identifying the usecases, to identify what the actors need from the system.
4. Looking for the common functionality that can be reused across the system.
5. Generalize the Actors and usecases to show the inheritance of the functions (where actors are associated with similar use cases while triggering few use cases unique only to them).
6. There are optional functions as well as additional functions - If some functions are triggered optionally, then we can use extend relationship.
« Last Edit: January 19, 2018, 03:48:28 pm by 1173025809 »

1171921109

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Re: How we draw a usecase diagram from a case study?
« Reply #14 on: January 21, 2018, 08:39:06 pm »
They also help identify any internal or external factors that may influence the system and should be taken into consideration.
When thinking of use cases, think of the end goal of a user. They don't want to "login" or "sign up." That's not a use case. The use case is more like "make a purchase."
Actors don't have names. They're not "Bob." They represent the role of someone interacting with the system.
Keep your names short and the size of your use cases consistent with a professional look.
For a detailed implementation of a user's goal using a sequence diagram.They provide a good high-level analysis from outside the system. Use case diagrams specify how the system interacts with actors without worrying about the details of how that functionality is implemented.
Draw your system's boundaries using a rectangle that contains use cases. Place actors outside the system's boundaries.
Use Case
Draw use cases using ovals. Label the ovals with verbs that represent the system's functions.
Actors
Actors are the users of a system. When one system is the actor of another system, label the actor system with the actor stereotype.
Relationships
Illustrate relationships between an actor and a use case with a simple line. For relationships among use cases, use arrows labeled either "uses" or "extends." A "uses" relationship indicates that one use case is needed by another in order to perform a task. An "extends" relationship indicates alternative options under a certain use case